Quarterback Sneak

What does Quarterback Sneak Mean?

A play in which the quarterback takes the snap from center and
immediately ducks forward behind the middle of the offensive line
with the intent of gaining a small amount of yardage. The
quarterback sneak is most often used in situations where the
distance required to gain a first down is one yard or less, since
the play is unlikely to gain more than that.

Sporting Charts explains Quarterback Sneak

The quarterback sneak is a common play on short yardage downs.
It is considered a low-risk play because the quarterback merely has
to take the snap and lean forward behind an offensive line that is
bent on driving the defense back from the line of scrimmage
immediately after the snap, rather than turning around to deliver a
handoff to a running back and risking a fumble or loss of yardage.
A defense will react to a potential sneak by attempting to clog up
the line immediately after the snap, forcing the quarterback to
change directions.